Gabapentin and Adderall Dosing When Used Together
When prescribing gabapentin and Adderall together, use standard dosing protocols for each medication independently, as there are no specific dose adjustments required for their combination, but monitor closely for additive CNS side effects.
Adderall Dosing Protocol
Starting Dose
- Immediate-release (IR): Begin with 5 mg twice daily (after breakfast and lunch) for adults, or 2.5 mg twice daily for children 1, 2
- Extended-release (XR): Start with 10 mg once daily in the morning 1, 2
- Morning administration is critical to minimize sleep disturbances 2
Titration Schedule
- Increase by 5-10 mg weekly increments for IR formulation 2
- Increase by 5 mg weekly for XR formulation 1, 2
- Allow at least one full week between dose increases to properly evaluate response 2
- Maintain weekly telephone contact during initial titration, with in-person visits at least monthly 2
Maximum Dose
- The maximum total daily dose is 40 mg according to the American Academy of Child and Adolescent Psychiatry 1
- Some recent guidelines suggest up to 50 mg daily for adults, but 40 mg remains the standard upper limit 1, 2
- If maximum dose is ineffective, do not increase further—consider switching medications instead 1, 2
Gabapentin Dosing Protocol
Starting Dose
- Begin with 100-300 mg at bedtime OR 100-300 mg three times daily 3
- Alternatively, start with 300 mg at bedtime and increase every 4-7 days by 300 mg increments 3
Titration Schedule
- Increase by 100-300 mg every 1-7 days as tolerated 3
- Initially titrate to three times daily dosing, then increase toward goal of 1,800 mg/day 3
- Gabapentin has nonlinear pharmacokinetics due to saturable absorption, requiring careful gradual titration 3
Maximum Dose
- Standard maximum: 3,600 mg/day divided into three doses 3
- Most patients achieve adequate response at 1,800 mg/day 3
- An adequate trial requires 3-8 weeks for titration plus 2 weeks at maximum tolerated dose 3
Critical Monitoring Parameters
For Adderall
- Baseline: Blood pressure, pulse, height, and weight 2
- Ongoing: Check blood pressure and pulse quarterly in adults 2
- Weigh at each visit to monitor for appetite suppression 1, 2
- Systematically assess for insomnia, anorexia, headaches, social withdrawal, and mood changes 1, 2
For Gabapentin
- Dose-dependent dizziness and sedation are common—reduced by starting low and titrating slowly 3
- Adjust dose in renal insufficiency based on creatinine clearance 3
- Monitor for neuropsychiatric adverse effects including somnolence, ataxia, tremor, and nystagmus 4, 5
Key Considerations for Combination Therapy
Additive CNS Effects
- Both medications cause sedation and dizziness—the combination may amplify these effects 3, 4
- Gabapentin causes dose-dependent sedation and dizziness 3
- Adderall can cause insomnia and agitation, which may partially offset gabapentin's sedating effects 1, 2
Dosing Strategy
- Start each medication at the low end of the dosing range when combining 3, 1
- Titrate one medication at a time to identify which agent is causing side effects
- Consider initiating gabapentin first and stabilizing before adding Adderall, or vice versa depending on clinical urgency
Renal Function
- Gabapentin requires dose reduction in renal insufficiency—adjust based on creatinine clearance 3
- Adderall does not require renal dose adjustment 1, 2
Common Pitfalls to Avoid
- Do not start both medications simultaneously at full doses—this increases risk of intolerable side effects
- Do not exceed Adderall 40 mg/day thinking more will help—efficacy plateaus and adverse effects increase 1, 2
- Do not rush gabapentin titration—saturable absorption means faster increases don't achieve higher levels 3
- Do not forget to adjust gabapentin in renal impairment—this is a critical safety consideration 3
- Do not overlook cardiovascular monitoring with Adderall—amphetamines increase blood pressure and heart rate 6